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Photoactive Functional Soft Materials (Preparation, Properties, and Applications) || Photoresponsive Polyolefins
摘要： Nature is unmatched in its esthetics and precisely controlled complexity of biochemical structures of life and the way they function. Nature’s sophisticated functional hierarchical structures are mostly made from biopolymers like polypeptides and polysaccharides, which, over time, have evolved to respond to various adverse external stimuli at levels ranging from molecular to macroscopic. The responses include change of color, shape, porosity, and stiffness. The most commonly used synthetic commodity polymers are polyolefins. But, just as most known synthetic polymers, functional properties of polyolefins are static. The challenge is to develop a commercially viable stimuli‐responsive polymer material, based on commodity polymers such as polyolefins. If we can make it respond to external stimuli, like light, such photoresponsive materials will have a wide range of applications in optical storage, sensors, actuators, artificial muscle, and soft‐robotics, etc. This chapter will discuss briefly the photoresponsive polymeric systems in general and the need for photoresponsive commodity polymers, followed by recent developments of photoresponsive polyolefins with suitable examples. Furthermore, the challenges and future directions of advancing the same are also discussed.
关键词： Photoresponsive,Actuators,Soft-robotics,Polyolefins,Commodity polymers,Stimuli-responsive,Light-responsive
更新于2025-09-23 15:21:01
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[Advances in Experimental Medicine and Biology] || Photoresponsive Hydrogels with Photoswitchable Stiffness: Emerging Platforms to Study Temporal Aspects of Mesenchymal Stem Cell Responses to Extracellular Stiffness Regulation
摘要： An extensive number of cell-matrix interaction studies have identi?ed matrix stiffness as a potent regulator of cellular properties and behaviours. Perhaps most notably, matrix stiffness has been demonstrated to regulate mesenchymal stem cell (MSC) phenotype and lineage commitment. Given the therapeutic potential for MSCs in regenerative medicine, signi?cant efforts have been made to understand the molecular mechanisms involved in stiffness regulation. These efforts have predominantly focused on using stiffness-de?ned polyacrylamide (PA) hydrogels to culture cells in 2D and have enabled elucidation of a number of mechano-sensitive signalling pathways. However, despite proving to be a valuable tool, these stiffness-de?ned hydrogels do not re?ect the dynamic nature of living tissues, which are subject to continuous remodelling during processes such as development, ageing, disease and regeneration. Therefore, in order to study temporal aspects of stiffness regulation, researchers have developed and exploited novel hydrogel substrates with in situ tuneable stiffness. In particular, photoresponsive hydrogels with photoswitchable stiffness are emerging as exciting platforms to study MSC responses to extracellular stiffness regulation. This chapter provides an introduction to the use of PA hydrogel substrates, the molecular mechanisms of mechanotransduction currently under investigation and the development of these emerging photoresponsive hydrogel platforms.
关键词： Photoswitchable stiffness,Biophysical regulation,Photoresponsive,Cell-matrix interaction,Regenerative medicine,Polyacrylamide,Mechanotransduction,Stiffness regulation,Mesenchymal stem cells,Cell adhesion,Temporal,Hydrogel substrates
更新于2025-09-23 15:21:01
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Size-Dependent Thermo- and Photoresponsive Plasmonic Properties of Liquid Crystalline Gold Nanoparticles
摘要： Achieving remotely controlled, reversibly reconfigurable assemblies of plasmonic nanoparticles is a prerequisite for the development of future photonic technologies. Here, we obtained a series of gold-nanoparticle-based materials which exhibit long-range order, and which are controlled with light or thermal stimuli. The influence of the metallic core size and organic shell composition on the switchability is considered, with emphasis on achieving light-responsive behavior at room temperature and high yield production of nanoparticles. The latter translates to a wide size distribution of metallic cores but does not prevent their assembly into various, switchable 3D and 2D long-range ordered structures. These results provide clear guidelines as to the impact of size, size distribution, and organic shell composition on self-assembly, thus enhancing the smart design process of multi-responsive nanomaterials in a condensed state, hardly attainable by other self-assembly methods which usually require solvents.
关键词： nanoparticles,photoresponsive materials,self-assembly,liquid crystals,surface plasmon resonance
更新于2025-09-23 15:19:57
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Metallopolymer Organohydrogels with Photoa??Controlled Coordination Crosslinks Work Properly Below 0 ?°C
摘要： Controlling the structures and functions of gels is important for both fundamental research and technological applications. Introducing photoresponsive units into gels enables remote control of their properties with light. However, existing gels show photoresponsiveness only at room temperature or elevated temperatures. The development of photoresponsive gels that work below 0 °C can expand their usage in cold environments. Here, photoresponsive metallopolymer organohydrogels that function even at ?20 °C are reported. The organohydrogels are prepared using photoresponsive Ru–thioether coordination bonds as reversible crosslinks to form polymer networks. A water/glycerol mixture is used as an anti-freezing solvent. At ?20 °C, the Ru–thioether coordination bonds are dissociated under light irradiation and reformed reversibly in the dark, which result in alternating crosslinking densities in the polymer networks. This process enables inducing reversible gel-to-sol transitions, healing damaged gels, controlling the mechanical properties and volumes of the gels, and rewriting microstructures on the gels below 0 °C.
关键词： photoresponsive materials,gels,crosslinks,anti-freezing,metallopolymers
更新于2025-09-23 15:19:57
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Controlled synthesis of azobenzene-containing block copolymers both in the main- and side-chain from SET-LRP polymers via ADMET polymerization
摘要： Novel ABA triblock copolymer contained azobenzene (azo) chromophores both in the main- and side-chain was designed and synthesized via combination of single electron transfer-living radical polymerization (SET-LRP) and acyclic diene metathesis (ADMET) polymerization. The α-bromoester end group of side-chain azo-polymer prepared in SET-LRP system using acrylate bearing azo group as monomer was reacted with potassium acrylate to yield azo-polymer with the chain end of α-acrylate, which acted as a monofunctional macromolecular chain stopper for subsequent ADMET polymerization of azo-functionalized α,ω-diene monomer to finally controllable synthesize ABA triblock azo-copolymer. The diluted solutions of main-chain ADMET azo-homopolymer, side-chain SET-LRP azo-homopolymer, and main-side chains azo-copolymer exhibited different photoisomerization behaviors (maximum absorption and rate of photoisomerization) under the irradiation of UV and visible light. All these interesting results could provide a guide for the design of photosensitive materials.
关键词： photoresponsive polymer,Single electron transfer-living radical polymerization,acyclic diene metathesis polymerization
更新于2025-09-19 17:13:59
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Improvement of Photoresponse in Organic Phototransistors through Bulk Effect of Photoresponsive Gate Insulators
摘要： In this study, we investigate the bulk effect of photoresponsive gate insulators on the photoresponse of organic phototransistors (OPTs), using OPTs with poly(4-vinylphenol) layers of two different thicknesses. For the photoresponse, the interplay between the charge accumulation (capacitance) and light-absorbance capabilities of a photoresponsive gate insulator was investigated. Although an OPT with a thicker gate insulator exhibits a lower capacitance and hence a lower accumulation capability of photogenerating charges, a thicker poly(4-vinylphenol) layer, in contrast to a thinner one, absorbs more photons to generate more electron–hole pairs, resulting in a higher photoresponse of the device. That is, in these two cases, the degree of light absorption by the photoresponsive gate insulators dominantly governed the photoresponse of the device. Our physical description of the bulk effect of photoresponsive insulators on the performance of OPTs will provide a useful guideline for designing and constructing high-performance organic-based photosensing devices and systems.
关键词： polymer gate insulator,photoresponsive polymer,organic phototransistor,bulk effect,poly(4-vinylphenol)
更新于2025-09-19 17:13:59
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Reconfigurable Surfaces Based on Photocontrolled Dynamic Bonds
摘要： Photocontrolled surfaces have attracted increasing interest because of their potential applications in lithography, photopatterning, biointerfaces, and microfluidics. Light provides high spatiotemporal resolution to control functions of such surfaces without getting into direct contact. However, conventional photocontrolled surfaces can only be switched between two states (on and off). The development of photocontrolled reconfigurable surfaces that can be switched among multiple states is highly desirable because these surfaces can adapt to rapid environmental changes or different applications. Herein, recent developments of photocontrolled reconfigurable surfaces are reviewed. Specially, reconfigurable surfaces based on photocontrolled reversible reactions including thiol-quinone methide, disulfide exchange, thiol-disulfide interconversion, diselenide exchange, and photosubstitution of Ru complexes are highlighted. As a perspective, other photocontrolled dynamic bonds that can be used to construct reconfigurable surfaces are summarized. Remaining challenges in this field are discussed.
关键词： reconfigurable surfaces,photoswitches,photochemistry,dynamic bonds,photoresponsive
更新于2025-09-12 10:27:22
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Synthesis and Characterization of Photoresponsive Macromolecule for Biomedical Application
摘要： Azobenzene, a photo switcher, has attracted increasing interest due to its structural response to photo stimulus in the field of information science and chemical sensing in the recent decades. However, limited water solubility and cytotoxicity restrained their applications in the biomedical field. In research, HA-AZO has been designed as a water soluble photo switcher in biomedical application. Synthesized HA-AZO had good water-solubility and a stable π-π? transition absorbance peak trans-isomer. With exposure to UV, transformation from trans-isomer to cis-isomer of HA-AZO could be realized according to UV spectra. Reversely, trans-isomer could be gradually recovered from cis-isomer in the dark. Simultaneously, quick response and slow recovery could be detected in the process of structural change. Moreover, repeated illumination was further used to detect the antifatigue property of HA-AZO, which showed no sign of fatigue during 20 circles. The influence of pH value on UV spectrum for HA-AZO was investigated in the work. Importantly, in acid solution, HA-AZO no longer showed any photoresponsive property. Additionally, the status of HA-AZO under the effect of UV light was investigated by DLS results and TEM image. Finally, in vitro cytotoxicity evaluations were performed to show the effects of photoresponsive macromolecule on cells.
关键词： photoresponsive macromolecule,photo switcher,biomedical application,hyaluronic acid,azobenzene
更新于2025-09-10 09:29:36
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Surface with Reversible Green-light-switched Wettability by Donor-Acceptor Stenhouse Adducts
摘要： In this report, we designed surfaces with reversible green-light-switched wettability by Donor-Acceptor Stenhouse adducts (DASAs). Photoresponsive micro/nanoparticles were prepared by coating polydopamine on the surface of silica micro/nanoparticles and then post-modifying with DASA molecules. Then, the particles were immobilized on glass substrates surface either by double-sided adhesive tapes or crosslinking polydimethylsiloxane. Silica micro/nanoparticles with various diameters (0.2, 2.5 and 85 μm) were used to fabricate the photoresponsive surface. Green light irradiation switches the hydrophobic linear DASA to hydrophilic cyclic isomer, which further increases the wettability and contact angle hysteresis on surface. On the other hand, heating (100 oC) induces the cyclic-to-linear isomerization of DASA molecules, and switches the surface back to hydrophobic. The wettability of the DASAs modified surface is reversible under alternately green light irradiating and heating.
关键词： donor-acceptor Stenhouse adducts,green light,surface,photoresponsive system,wettability
更新于2025-09-10 09:29:36
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A Photoresponsive Hyaluronan Hydrogel Nanocomposite for Dynamic Macrophage Immunomodulation
摘要： Macrophages are a predominant immune cell population that drive inflammatory responses and exhibit transitions in phenotype and function during tissue remodeling in disease and repair. Thus, engineering an immunomodulatory biomaterial has significant implications for resolving inflammation. Here, a biomimetic and photoresponsive hyaluronan (HA) hydrogel nanocomposite with tunable 3D extracellular matrix (ECM) adhesion sites for dynamic macrophage immunomodulation is engineered. Photodegradative alkoxylphenacyl-based polycarbonate (APP) nanocomposites are exploited to permit user-controlled Arg–Gly–Asp (RGD) adhesive peptide release and conjugation to a HA-based ECM for real-time integrin activation of macrophages encapsulated in 3D HA–APP nanocomposite hydrogels. It is demonstrated that photocontrolled 3D ECM–RGD peptide conjugation can activate αvβ3 integrin of macrophages, and periodic αvβ3 integrin activation can enhance anti-inflammatory M2 macrophage polarization. Altogether, an emerging use of biomimetic, photoresponsive, and bioactive HA–APP nanocomposite hydrogel is highlighted to command 3D cell–ECM interactions for modulating macrophage polarization, which may shed light on cell–ECM interactions in innate immunity and inspire new biomaterial-based immunomodulatory therapies.
关键词： macrophages,hyaluronan,photoresponsive biomaterials,hydrogel nanocomposites,immunomodulation
更新于2025-09-09 09:28:46